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1.
1 Introduction  China is rich in rare- earth,reserves of it occupy80 % of that of the whole world,as resources of rare-earth waste is becoming serious social problem day by day.As to rare- earth material factories in Harbin( these factories are small and medial scales) ,nearly1 0 0 0 ton waste is stored up and because of its pilingup,the nearby hilly area is become deharvested.Health of human and livestock is greatly harmed.Compo-nents of the waste contain radioactive nuclide2 3 2  Th,and…  相似文献   

2.
The taxonomic status of the medicinal plants in Jordan is expressed in terms of its diversity, the documentation of the scientific research that is carried out locally over the last many years; to test for the potential of some medicinal plant species (MPS) in Jordan on different biological aspects is also prepared. This has been reported here by revising and documenting the available literature to the author on this subject. The ecological status of medicinal plants in Jordar is also pointed out. The aim of this research was mainly to evaluate the status of the research on medicinal plants that was carried oul: to test for the different biological potentials of medicinal plants in Jordan and to emphasis the richness of the country of its wild medicinal plants, which are of promising value in whether for use in traditional medicine or in pharmaceutical industry, and certainly need lots of investigations and scientific research. Photographs of some medicinal plants that are common in Jordan and are used in traditional medicine in the urban areas and the Badia region, which is located in the Eastern part of the country and characterized by its dry weather conditions and least amount of rainfall in the country, are also included; the plant photographs are selected from different representative families of the common flowering plants in Jordan.  相似文献   

3.
Ethiopia is the third populous country in Africa. The 17 years of military government (Derg) period 1974-1991 witnessed a centralized economic system and the post-Derg reform has taken the way of market-oriented system for 10 years. Economic and social achievements are observed in Ethiopia during the reform period.   ……  相似文献   

4.
Fruit protected cultivation in China   总被引:1,自引:0,他引:1  
Protected fruit cultivation in China has developed very quickly from the early 1990s, and now it is animportant branch in fruit cultivation. A brief review including fruit species, developing history, growing area, output, and distribution in the whole country is made in the paper. Characteristics of the dominant kinds of greenhouse,environmental control methods, and standards of temperature, humidity, light and CO2 for different fruit species are presented. Information on varieties, growing benefits, special management practices and other aspects of the main fruit species used for protected cultivation are also presented.  相似文献   

5.
China is the world’s most populous country and a major emitter of greenhouse gases. Consequently, China’s role in climate change has received a great deal of attention, whereas the impact of climate change on China has been largely ignored. Studies on the impacts of climate change on agriculture and adaptation strategies are increasingly becoming major areas of scientific concern. However, the clear warming that has been sounded in China in recent decades has not been matched with a clear assessment of the impact of climate change on China’s water resources and agriculture. In the present study, we review observations on climate change, hydrology, and agriculture in China and relate these observations to likely future changes. We also analyse the adaptive strategies in China’s agriculture.  相似文献   

6.
A method of LEO autonomous navigation is presented based on the nonlinear satellite velocity relative to the earth. The velocity is detected by a high-speed camera, with the attitude information detected by a star sensor. Compared with traditional autonomous navigation by landmark identification, the satellite velocity relarive to the earth is obtained by correlativity analysis of images. It does not need to recognize ground objects or views. Since it is not necessary to pre-store the database of ground marks, lots of memory space can be saved.The state and observation equations are constructed, and the filtering is processed by the Kalman filter. Simulation results show that the system has high autonomous navigation precision in LEO autonomous navigation.  相似文献   

7.
8.
By the end of sixties, several satellites were launched to observe the earth; among them the Landsat missions have been important to study natural resources, especially in agriculture. Currently, Landsat 7, with some problems, and Landsat 5 are useful to evaluate crop development. A project called "Participatory multi-Level EO-assisted tools for Irrigation water management and Agricultural Decision-Support" (PLEIADES) was financed by the European Commission. This project considers eleven countries and 23 research institutions, Mexico being one of the selected countries. Landsat images are a basic tool of this project. Some of the results obtained in this study are presented in this article. By using w~getation indices obtained by the combinations of reflectances in different bands of the electromagnetic spectrum, it has been possible to estimate the behavior of several biophysical parameters of crops which are used to evaluate plant development, water stress, spatial soil variation, and the effect of plagues and crop diseases. To facilitate this process, a visor was developed, named SPIDER (System of Participatory Information Decision support and Expert knowledge for River basin management) whose use in this work is explained.  相似文献   

9.
Since industrial revolution, the atmospheric CO2 concentration has kept a continuous increase by more than 2.2 ppm yr^-1, and approaches to almost 400 ppm at present (Jouzel 2012). China has become the largest country of greenhouse gas emission (GHG), and confronts with great challenge to mitigate GHG.  相似文献   

10.
This paper presented a conceptual framework to country competitiveness using the Index of Competitiveness (IVCR), revealed for Ecuador to determine the most competitive and potential products exported to China; also measured the export complementarities through other indicators and by comparison with similar products exported by competing countries. This study used the 6-digit Harmonized System (HS) and the 10-digit NANDINA tariff codes for more specific items. Thereby we can identify trends that allow the Ecuadorian authorities analyze the state of bilateral agreements and develop action strategies, moreover help exporters identify potential market niches, considering that China is currently one of the developing countries with higher growth and expanding economy. The results showed that the most competitive agricultural products consisted on fish flour, bovine skins, mollusks, fish wastes and cocoa grains. The founded potential products were broad beans, fruits, fish viscera, algae, alpaca hair or hair wastes. Nevertheless these were none adding value commodities we need to find some mechanisms to deepen the exportable offer of value-added goods.  相似文献   

11.
胡志锋  孙静 《安徽农业科学》2007,35(29):9320-9321,9328
利用筛选出的优势菌种在四川维尼纶厂进行了废水处理工程的技术改造研究。结果表明,DO和COD的检测值显示废水在曝气池中分布不均,有短流现象存在;进行技术改造后,相同条件下较以前对COD的去除率提高5%左右,系统的处理能力提高20%~30%,曝气停留时间缩短2 h,填料可提高COD的平均去除率为7.9%;并且试验后续1个月的运行结果表明系统运行状况良好。  相似文献   

12.
[目的]研究不同有机负荷条件下曝气时间对SBR系统的影响。[方法]通过改变进水有机负荷及曝气时间,了解不同有机负荷运行条件下,曝气时间对SBR系统的影响。[结果]搅拌/曝气时间分别为2.5 h/7.5 h时,COD与TP的去除效果最佳。此时,在低、中有机负荷运行条件下,COD和TP的出水浓度均达到了《城镇污水处理厂污染物排放标准》(GB18918-2002)一级B标准。而高有机负荷运行条件下,COD和TP的出水浓度均未达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级B标准,但COD和TP的去除效果较高。[结论]不同有机负荷条件下,曝气时间对SBR系统有明显影响。  相似文献   

13.
含三唑磷农药废水的光降解研究   总被引:9,自引:1,他引:9  
对含三唑磷废水光氧化降解的可行性研究表明,直接光解可有效提高含三唑磷水样的可生化性,经6h光照后,水样的BOD5/COD由0.22提高到0.70;添加H2O2对光解效果有一定改善作用,投加量达到75mg/L时,水样的COD去除率由零投加时的20%提高到40%,但过量投加对处理效果没有进一步促进作用,同时比较了在曝气和不曝气两种条件下采用UV,UV/H2O2,UV/Fenton,UV/类Fenton等4种工艺对三唑磷废水的处理情况,结果表明,UV/H2O2,UV/Fenton,UV/类Fenton工艺较单纯UV工艺对水样的COD去除效果有显著提高;曝气能促进光解效果,特别对UV/Fenton工艺作用更为显著,光解水样2h后,曝气条件下的COD去除率可从不曝气条件下的30%提高到80%。  相似文献   

14.
SBR法处理生活工业综合污水的可行性研究   总被引:3,自引:0,他引:3       下载免费PDF全文
采用SBR (Sequencing Batch Reactor)工艺进行了生活工业综合污水处理的可行性研究.结果表明:曝气时间与处理效率、污泥活性密切相关;当进水COD为430~660 mg/L,NH4+-N为16.9~21.5 mg/L时,曝气10 h能取得较好的效果,COD去除率可达90%,出水COD<80 mg/L,NH4+-N<14 mg/L.  相似文献   

15.
为提高水稻秸秆在好氧厌氧两相发酵工艺中降解率,采用好氧水解阶段添加不同菌剂方法提高好氧产酸相纤维素降解率。结果表明,各处理组中木霉和黑曲霉混菌组较单一菌种组纤维素和半纤维素降解率更高,水解效果更好。其中木霉黑曲霉混菌曝气组,总酶活最高,纤维素和半纤维素降解效果最好,累积产甲烷量最高,TS产气量最高达到438.57 m L·g-1。由此可见,木霉、黑曲霉混菌并同时曝气供气方式能显著提高水稻秸秆固体有机物降解利用率,促进秸秆生物质转化为沼气。  相似文献   

16.
彭乾  张鉴达  梁剑 《安徽农业科学》2011,39(34):21231-21232,21296
[目的]研究SBR反应器中好氧颗粒污泥处理模拟废水的反应特性。[方法]将SBR好氧颗粒污泥反应器应用于模拟废水的处理,研究反应器中溶解氧随曝气强度的变化规律,并探讨一个反应周期内COD、TN、TP去除率的变化。[结果]不同曝气强度下,SRB反应器开始曝气时(第11 min)溶解氧值均最低,之后呈上升趋势,均在第13 min出现第一个"平台",且曝气强度越大,该"平台"越高;50min后溶解氧值波动较小。反应周期结束时,不同气速下COD、TN、TP去除率分别达98%、75%、80%以上,且不同气速对污染物的去除有一定影响。[结论]该研究为今后废水处理工程的实际应用提供了技术指导。  相似文献   

17.
应用仔猪20头,以猪囊尾蚴“四性细胞系”的可溶性抗原作为免疫原,对经过第1次用不同细胞剂量疫苗免疫的猪,再次用与细胞数量相适应的细胞代射产物的不同剂量疫苗,对其中的11头进行第2次免疫以第2次还是注射细胞疫苗的3头、只注射1次细胞疫苗的2头,和空白对照猪2头作对照组,以观察代射产物抗原的免疫原性。于第1次细胞疫苗免疫后的68d,最长94d用细胞加代谢产物疫苗进行了这次免疫,14d后攻虫,每头使用人有钩绦虫卵,6000枚,3个月后屠宰检查虫体。第1次用10万细胞疫苗免疫,第2次用1千万细胞加代谢产物疫苗免疫该组动物中的2头,平衡有5个囊尾蚴,但这2头猪均发生了囊尾蚴钙化;另一组第1次用100万细胞疫苗免疫,第2次用2千万细胞加代谢产物疫苗免疫该组全部3头动物,平均有3.6个囊尾蚴,这3头猪也都有囊尾蚴钙化。2个实验组出现免疫猪的100%的钙化现象,是免疫治疗作用,是猪囊尾蚴四性细胞系代谢产物的特殊免疫作用。  相似文献   

18.
以造纸废弃物白泥作为pH调节剂,利用MAP沉淀法回收厌氧消化液中的氮磷,并采用曝气的方式提高消化液pH值和造纸白泥的溶解性,研究了造纸门泥的添加量和曝气时间对厌氧消化液中氮、磷回收效果的影响,并考察了曝气过程中pH、COD、PO3-4-P、NH3-N、Mg2+、Ca2+的变化规律.结果表明:造纸白泥的添加量为8 g·L-1,曝气时间为120 min时,PO3-4-P和NH3-N的回收率分别达到98%和59%,出水的PO3-4-P和NH3-N浓度分别为0.98 mg·L-1和60.66 mg·L-1,均达到了<畜禽养殖业污染物排放标准))(GBl8596-2001)的要求,同时,COD的去除率为45%;如果仅用曝气方式处理,120 min后PO3-4-P和NH3-N的回收率仅分别为66%和41%,均未达到排放标准要求.可见,与仅用曝气方式处理相比,添加造纸白泥协同曝气对厌氧消化液中氮磷的回收有明显的效果.  相似文献   

19.
为研究不同种植密度和曝气条件下,沉水植物金鱼藻对寒区静水湿地水体净化作用和微生物群落变化的影响,从寒区静水湿地水体采集样品,在实验室投加金鱼藻的固定容器中进行曝气处理,测定总氮(total nitrogen, TN)、总磷(total phosphorus, TP)的去除效果;利用高通量测序技术分析不同时间和不同处理间水体微生物群落结构和多样性变化,结合水体理化因子分析微生物群落变化的影响因素。结果表明:结合金鱼藻用量和能耗,金鱼藻种植密度为4.44 g·L-1,曝气12 h条件下可达到良好的水体净化效果,TN、TP的去除率分别为51.23%、89.27%。微生物样品测序共得到3 283个操作分类单元(operational taxonomic units,OTU),核心OTU数量为107个,对照组中特有OTU数量较多。总体上看,各组微生物群落多样性均未增加,组间差异显著性逐渐降低;优势门为变形菌门、拟杆菌门和放线菌门,投加适量金鱼藻可提高优势门的相对丰度,但曝气处理使变形菌门、拟杆菌门相对丰度降低。不同样品间微生物属水平上存在较大比例的未分类类群,变形菌门多核杆菌属具有较高的相对丰度,投加适量金鱼藻和曝气处理有利于提高其相对丰度。与对TN、TP浓度变化的影响相比,投加金鱼藻和曝气处理对微生物优势类群影响更加显著。  相似文献   

20.
不同环境条件对韭菜水溶性浸提液抑藻效果的影响(英文)   总被引:1,自引:0,他引:1  
[目的]研究不同环境条件对韭菜水溶性浸提液抑藻效果的影响,为进一步研究和开发新的抑藻物质提供参考。[方法]通过设置不同的pH、光照强度以及曝气与否,对不同条件下韭菜浸提液对铜绿微囊藻生长的影响进行了对比研究。[结果]在7d的培养过程中,不同pH条件下,韭菜浸提液对铜绿微囊藻的生长抑制均达到90%以上,随着铜绿微囊藻的生长,不同起始pH的培养液,最终的pH趋向于9.0~9.5之间;在1000~4000lx的光强范围内,韭菜浸提液对藻细胞的生长抑制率均随培养时间的延长而增加,低光照强度(1000lx)下,韭菜浸提液对铜绿微囊藻抑制效果要好于高光照强度处理,即最佳的生长光照强度并不有利化感作用的发挥;同时,曝气相对非曝气条件而言,曝气条件更有利于韭菜浸提液对铜绿微囊藻生长的抑制。[结论]该研究结果表明pH、光照强度、是否曝气均影响韭菜水溶性浸提液高温处理后对铜绿微囊藻的抑制效果。探讨这些环境因子对植物化感物质抑藻效果的影响,可为进一步研究和开发新的抑藻物质提供参考。  相似文献   

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